GI GI Anatomy and Physiology 1 — Questions and Answers
Question 1: Which layer of the GI tract contains blood vessels, lymphatics, and the submucosal (Meissner's) plexus?
- Mucosa
- Submucosa (Correct answer)
- Muscularis externa
- Serosa
Correct answer: Submucosa
The submucosa houses Meissner's plexus along with blood vessels, lymphatics, and connective tissue.
Question 2: What is the primary function of the ileocecal valve?
- Absorb vitamin B12
- Prevent backflow of colonic contents into the ileum (Correct answer)
- Secrete digestive enzymes
- Regulate gastric emptying
Correct answer: Prevent backflow of colonic contents into the ileum
The ileocecal valve prevents reflux of bacteria-laden colonic contents back into the small intestine.
Question 3: Which cells in the gastric mucosa produce intrinsic factor?
- Chief cells
- G cells
- Parietal cells (Correct answer)
- Mucous neck cells
Correct answer: Parietal cells
Parietal cells secrete both hydrochloric acid and intrinsic factor, which is essential for vitamin B12 absorption.
Question 4: Brunner's glands, which secrete alkaline mucus to protect the duodenal mucosa, are located in which layer?
- Mucosa
- Submucosa (Correct answer)
- Muscularis externa
- Serosa
Correct answer: Submucosa
Brunner's glands are submucosal glands unique to the duodenum that secrete bicarbonate-rich mucus.
Question 5: The migrating motor complex (MMC) phase III is characterized by which activity?
- Complete motor quiescence
- Irregular contractions
- Intense, regular contractions sweeping the gut (Correct answer)
- Random, low-amplitude contractions
Correct answer: Intense, regular contractions sweeping the gut
Phase III MMC produces intense, cyclical contractions that sweep from stomach to ileum, clearing residual contents during fasting.
Question 6: Which segment of the colon has the highest rate of water and electrolyte absorption?
- Sigmoid colon
- Descending colon
- Transverse colon
- Ascending (right) colon (Correct answer)
Correct answer: Ascending (right) colon
The ascending colon absorbs the majority of water and electrolytes from liquid ileal effluent, producing semi-solid stool.
GI GI Anatomy and Physiology 1
Which layer of the GI tract contains blood vessels, lymphatics, and the submucosal (Meissner's) plexus?